2 * OMAP4 CPU idle Routines
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 * Santosh Shilimkar <santosh.shilimkar@ti.com>
6 * Rajendra Nayak <rnayak@ti.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #include <linux/sched.h>
14 #include <linux/cpuidle.h>
15 #include <linux/cpu_pm.h>
16 #include <linux/export.h>
17 #include <linux/clockchips.h>
19 #include <asm/proc-fns.h>
25 #ifdef CONFIG_CPU_IDLE
27 /* Machine specific information to be recorded in the C-state driver_data */
28 struct omap4_idle_statedata {
35 static struct cpuidle_params cpuidle_params_table[] = {
36 /* C1 - CPU0 ON + CPU1 ON + MPU ON */
37 {.exit_latency = 2 + 2 , .target_residency = 5, .valid = 1},
38 /* C2- CPU0 OFF + CPU1 OFF + MPU CSWR */
39 {.exit_latency = 328 + 440 , .target_residency = 960, .valid = 1},
40 /* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
41 {.exit_latency = 460 + 518 , .target_residency = 1100, .valid = 1},
44 #define OMAP4_NUM_STATES ARRAY_SIZE(cpuidle_params_table)
46 struct omap4_idle_statedata omap4_idle_data[OMAP4_NUM_STATES];
47 static struct powerdomain *mpu_pd, *cpu0_pd, *cpu1_pd;
50 * omap4_enter_idle - Programs OMAP4 to enter the specified state
51 * @dev: cpuidle device
52 * @drv: cpuidle driver
53 * @index: the index of state to be entered
55 * Called from the CPUidle framework to program the device to the
56 * specified low power state selected by the governor.
57 * Returns the amount of time spent in the low power state.
59 static int omap4_enter_idle(struct cpuidle_device *dev,
60 struct cpuidle_driver *drv,
63 struct omap4_idle_statedata *cx =
64 cpuidle_get_statedata(&dev->states_usage[index]);
65 struct timespec ts_preidle, ts_postidle, ts_idle;
69 int cpu_id = smp_processor_id();
71 /* Used to keep track of the total time in idle */
72 getnstimeofday(&ts_preidle);
78 * CPU0 has to stay ON (i.e in C1) until CPU1 is OFF state.
79 * This is necessary to honour hardware recommondation
80 * of triggeing all the possible low power modes once CPU1 is
81 * out of coherency and in OFF mode.
82 * Update dev->last_state so that governor stats reflects right
85 cpu1_state = pwrdm_read_pwrst(cpu1_pd);
86 if (cpu1_state != PWRDM_POWER_OFF) {
87 new_state_idx = drv->safe_state_index;
88 cx = cpuidle_get_statedata(&dev->states_usage[new_state_idx]);
92 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);
95 * Call idle CPU PM enter notifier chain so that
96 * VFP and per CPU interrupt context is saved.
98 if (cx->cpu_state == PWRDM_POWER_OFF)
101 pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
102 omap_set_pwrdm_state(mpu_pd, cx->mpu_state);
105 * Call idle CPU cluster PM enter notifier chain
106 * to save GIC and wakeupgen context.
108 if ((cx->mpu_state == PWRDM_POWER_RET) &&
109 (cx->mpu_logic_state == PWRDM_POWER_OFF))
110 cpu_cluster_pm_enter();
112 omap4_enter_lowpower(dev->cpu, cx->cpu_state);
115 * Call idle CPU PM exit notifier chain to restore
116 * VFP and per CPU IRQ context. Only CPU0 state is
117 * considered since CPU1 is managed by CPU hotplug.
119 if (pwrdm_read_prev_pwrst(cpu0_pd) == PWRDM_POWER_OFF)
123 * Call idle CPU cluster PM exit notifier chain
124 * to restore GIC and wakeupgen context.
126 if (omap4_mpuss_read_prev_context_state())
127 cpu_cluster_pm_exit();
130 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu_id);
132 getnstimeofday(&ts_postidle);
133 ts_idle = timespec_sub(ts_postidle, ts_preidle);
138 idle_time = ts_idle.tv_nsec / NSEC_PER_USEC + ts_idle.tv_sec * \
141 /* Update cpuidle counters */
142 dev->last_residency = idle_time;
147 DEFINE_PER_CPU(struct cpuidle_device, omap4_idle_dev);
149 struct cpuidle_driver omap4_idle_driver = {
150 .name = "omap4_idle",
151 .owner = THIS_MODULE,
154 static inline void _fill_cstate(struct cpuidle_driver *drv,
155 int idx, const char *descr)
157 struct cpuidle_state *state = &drv->states[idx];
159 state->exit_latency = cpuidle_params_table[idx].exit_latency;
160 state->target_residency = cpuidle_params_table[idx].target_residency;
161 state->flags = CPUIDLE_FLAG_TIME_VALID;
162 state->enter = omap4_enter_idle;
163 sprintf(state->name, "C%d", idx + 1);
164 strncpy(state->desc, descr, CPUIDLE_DESC_LEN);
167 static inline struct omap4_idle_statedata *_fill_cstate_usage(
168 struct cpuidle_device *dev,
171 struct omap4_idle_statedata *cx = &omap4_idle_data[idx];
172 struct cpuidle_state_usage *state_usage = &dev->states_usage[idx];
174 cx->valid = cpuidle_params_table[idx].valid;
175 cpuidle_set_statedata(state_usage, cx);
183 * omap4_idle_init - Init routine for OMAP4 idle
185 * Registers the OMAP4 specific cpuidle driver to the cpuidle
186 * framework with the valid set of states.
188 int __init omap4_idle_init(void)
190 struct omap4_idle_statedata *cx;
191 struct cpuidle_device *dev;
192 struct cpuidle_driver *drv = &omap4_idle_driver;
193 unsigned int cpu_id = 0;
195 mpu_pd = pwrdm_lookup("mpu_pwrdm");
196 cpu0_pd = pwrdm_lookup("cpu0_pwrdm");
197 cpu1_pd = pwrdm_lookup("cpu1_pwrdm");
198 if ((!mpu_pd) || (!cpu0_pd) || (!cpu1_pd))
202 drv->safe_state_index = -1;
203 dev = &per_cpu(omap4_idle_dev, cpu_id);
206 /* C1 - CPU0 ON + CPU1 ON + MPU ON */
207 _fill_cstate(drv, 0, "MPUSS ON");
208 drv->safe_state_index = 0;
209 cx = _fill_cstate_usage(dev, 0);
210 cx->valid = 1; /* C1 is always valid */
211 cx->cpu_state = PWRDM_POWER_ON;
212 cx->mpu_state = PWRDM_POWER_ON;
213 cx->mpu_logic_state = PWRDM_POWER_RET;
215 /* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
216 _fill_cstate(drv, 1, "MPUSS CSWR");
217 cx = _fill_cstate_usage(dev, 1);
218 cx->cpu_state = PWRDM_POWER_OFF;
219 cx->mpu_state = PWRDM_POWER_RET;
220 cx->mpu_logic_state = PWRDM_POWER_RET;
222 /* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
223 _fill_cstate(drv, 2, "MPUSS OSWR");
224 cx = _fill_cstate_usage(dev, 2);
225 cx->cpu_state = PWRDM_POWER_OFF;
226 cx->mpu_state = PWRDM_POWER_RET;
227 cx->mpu_logic_state = PWRDM_POWER_OFF;
229 drv->state_count = OMAP4_NUM_STATES;
230 cpuidle_register_driver(&omap4_idle_driver);
232 dev->state_count = OMAP4_NUM_STATES;
233 if (cpuidle_register_device(dev)) {
234 pr_err("%s: CPUidle register device failed\n", __func__);
241 int __init omap4_idle_init(void)
245 #endif /* CONFIG_CPU_IDLE */